Dental plaque is a biofilm that adheres to tooth and other oral surfaces, particularly at the gingival margin, and is implicated in the occurrence of gingivitis, periodontitis, caries and other forms of periodontal disease. Dental plaque is cohesive and highly resistant to removal from teeth and/or oral surfaces. Dental plaque comprises glucans, which are insoluble polysaccharides that provide plaque with its cohesive properties. The bacterial enzyme glucosyltransferase converts dietary sugar into glucans. Plaque mineralizes to form a hard deposit called calculus (or tartar), which becomes a local irritant for the gums, causing gingivitis.
Various antibacterial agents can retard the growth of bacteria and thus reduce the formation of biofilm on oral surfaces.
Zinc and other metal compound/salts have been previously used as antibacterial agents. Without being bound by any theory, free zinc ions are believed to provide antibacterial efficacy by inhibition of glucose metabolism and/or interaction with the bacterial cell wall, reducing bacterial colonization of the oral cavity (as discussed in Cummins D., J Clin Periodontol 1991; 18; 455-461). An insoluble zinc compound, zinc oxide, could also deliver strong antibacterial efficacy during tooth brushing.
It would be desirable to provide an oral care composition which exhibits even greater efficacy than previously-known compositions in its reduction of biofilm.